Fuse plug



Dec. 4, 1928. 1,693,679 M. H. TERRY FUSE PLUG Filed Oct. 2l, 1926 f ni Qwuemtoc Mms,

Patented Dec. yl, 1928.

UNITED STATES VM'EI/EILL H. TERRY,

or COLUMBUS, oHIo.

.FUSE PLUG.

Application-tiled October 21, 1926.

i This invention relates to improvements in fuse plugs of the type embodying a removable or replaceable fuse clement which, when destroyedby an abnormal condition in an associated electric circuit, may be readily removed from the body of the plug .and a new element substituted therefor' in a. simple and easily accomplished manner. Y y

object in the invention resides in the provision of al fuse plugA ofthecharacter specified wherein the permanent body of-the plug has the outer end thereof provided with an axially disposed socket in which is pro- .vided spaced resilient contact members, the said socket being adapted to receive a removable cartridge which carries a fusible element 'or strip, the arrangement being such that when the cartridge occupies an operative po- ,.fsition within the'socket, the fusible element y ,.tridge.

, ternal inspection, the

, the fuse plug wherein thereof is resiliently engaged by the contact members so as to provide an c'lective electrical and mechanical connection between said members 'and the .fusible element' of the car- A'notherobje'ct resides in tridge to include asubstantial transparent closure by Whichthe condition of the fusible element or strip may -be-observed by an exclosure comprising an integral part of the cartridge assembly and is removable-with said fusible clement in an unita-ry manner.

Another object resides in thc provision of the cartridge unit is removable from the body of the plug from the front or outer end of the latter and without necessitating the removal of the plug body from an associated electric socket.

With these and other objects in view, which will appear as the description proceeds, the invention consists in the novel feature of construction, combination of elements and arrangement of parts hereinafter fully described and particularly pointed out in the appended claims.

In the accompanying drawings, which show an embodin'ient of the invention:

Fig. l is a vertical sectional view taken thru the plug.

Fig. `2 is a top plan View thereof.

Fig. 3 is a detail perspective view of the removable cartridge unit of the plug.

eferring more particularly te the drawing, the numeral 1 designates the body of the fuse plug. This body is preferably of one piece construction and is formed from porforming the car- Serial No. 143,255.

celain, composition or .other insulating matcrial. The body includes the usual enlarged central outer portion 2 externally knurled or roughened as at 3 to permit of its convenient handling. The inner or lower part of the body is reduced in diameter and is formed to include av threaded metallic sleeve 4, permanently held in place on said body. In this instance the body l has the outer end provided with an axially disposed socket 5 which extends well into the body oftheplug. Positioned within said socket is a pair of spaced resilient contact arms 6 and 7, which are disposed contiguous to side Walls of the socket. The arm 6 terminates in a downwardly and obliquely extending portion 8 which passes thru an angular slot provided inthe body l and extends between the outer surface of said body and the socket. The downwardly -extending portion 8 of said arm terminatessin a curved or corrugated portion 9, which, in practice, is confined between sleeve 4 and adjacent cuter wall of body 1,v so as to provide a secure mechanical'mounting for said arm and a good electrical contact with the sleeve 4. The arm 7 ,which is spaced from the arm 6, includes lan elongated shank portion =10, which in this instance passes axially thru the inner or lower part of the body l, the extreme lower end of the shank being provided with a head ll .arranged exteriorly in a' central position upon the lower or inner end of said body. The shank l() is bent to extend parallel to the lower or inner -wall of the socket 5, and is then bent perpendicularly to provide the arm 7 proper. The arms 6 and 7 are spaced sufficiently from the adjacent walls of the socket 5 to permit of their relative spreading when they are resiliently forced apart.

The construction of the plug so far described constitutcs the permanent part thereof, and in association therewith the invention provides a removable or replaceable cartridge unit which is designed in its entirety by the numeral l2. venieutly removable manner wit-hin the socket 5 and the construction of said yunit is Such that the same may be renewed from time to time with but minimum expense. In the embodiment of the invention herein described the. said unit consists of a shell lofinsulating material having the'outer rim thereof provided with a metallic reinforcing ring 14, adapted for the reception and permanent connection of a. transparent closure disc 15, which This unit is receivable in` a conis preferably-formed frommica or some other suitable semi-transparent material. The slie'il is slotted at its inner end as at 15 to receive guide ribs 16 formed with the walls of the socket 5, the construction serving to insure the positioning of the removablecartridge in a predeterinincd manner within the socket. c

The lower or inner end of the shell 13 accomodates the U shaped ends 18 of a fusible contact strip or element 19. It will be ob- Served that the manner of mounting the. strip in connection with the shell is such as to -enable the ends 1S to extend substantially par- 15 allelto the arms 6 and 7, which will be engaged by the contact strip and resiliently forced Vapart to a slight' extent, ena-bling said arms to Aexercise resilient Ypressure on -the armS-18of the contactjstrip to provide: first,

2o a good .electrical connection 'between said arms and the contact strip and,' second, a means for mechanically retaining the `cartridge unit in its applied position within thev socket. Around the outer end of the socket 5, there is provided in the body 1 an 'annular seat 20 which receives the bead 14 of said cartridge and limit-s the inward movement thereof; One or moi'e notches 21 may be formed in the body 1 adjacent the seat 20 to permitof the insert-ion of a. tool or the like beneaththe bead 14a-nd facilitate the iemoval of cartridge unit from the socket.

vIn view ofthe foregoing, it will be seen that in the event the fusible strip 19 is destroyed by an abnormal condition or over load in an associated electric circuit, the cartridge'unit may be readily removed from the Vvbody by outward sliding movement and a new unit inserted in the body in place thereof. It

40 will be observed that by forming the socket 5 at the outer end of said body this substitution or replacement can be accomplished without necessitating the entii'e removal of the plug from its associated socket. In practice, it is necessary merely to rotate the plug that., when the fuse plugs are mounted in groups, the defective plug may be readily ascertained at a glance.

I do not desire to limit my invention to the precise details of construction and arrange- U ment as herein set forth as it is obvious that various modifications -may be made therein without departing from the essential features of my invention as defined in the appended claims.

iV hat is claimed is:

l. A fuse plug comprising a body having one end thereof formed with an axially disposed sockct, spaced resilient contact members mounted in connection with said body and extending in theginner part of said socket, a removable shell formed to occupy said socket, a-fusiblevcontact'strip carried by inner part-ofsaid shell-:and adapted for fric tional eneagement with 'said contact-ineinbers,a substantially1 -transparent closure car.

ried-by outer end of said Shell and guide means-for` retaining said shell in a predeterminedposition within said socket.

2. A fuse plug comprising a body having.

afsocket provided in one end thereof, space contactv members carried by said bodyand arranged 'adjacent .to 'the inner-end of -said socket, a shell of .insulating material formed to removably'occupy'said socket, 'a fuse strip carried bylthe inner-'part of said shell and adapted for frictional engagement with said contact members, said strip being disposed transversely of said socket, and means formed with said body and shell-for guiding the latter into a predetermined position within said shell.

3. VA fuse plug comprising a body havingan axially disposed cylindrical bore formed in one end'tliereof, arpairfofspaced contact members carried by said body and having portions thereof extending vertically :along the inner walls ofsaid boi'e and arranged adjacentthe inner end thereof, a cylindrical shell of insulating material formed to removably occupy said bore, a fuse strip carried by the inner part of said shell anddisp'osed transversely thereof, said fuse strip having portions thereof extending` vertically along the outer walls of said shell and arranged to frict-ionally engage with the vertical portions of said contact members, a transparent closure carried by the outer end of said bore, and means formed with the body and shell for retaining the latter in a predetermined position within said bore.

4. A fuse plug comprising a body having an open ended bore axially disposed'therein, a pair of spaced contact members carried by said body and extending in the inner part of said bore, a removable shell formed to occupy said bore, a fusible strip carried by the inner partof said shell and adapted for frictional engagement with said contact members, a substantially transparent closure carried by the outer end of said shell. and means formed with the outer end of said Shell for facilitatin;T its removal from said bore.

In testimony whereof I afiix my signature.

MERRILL H. TERRY. 

